Field of the Invention
The invention relates to a mounting configuration of electric and/or electronic components on a printed circuit board.
Such a mounting configuration is disclosed in Published, Non-Prosecuted German Patent Application DE 41 07 312 A1. There, an electronic component is disposed on a printed circuit board which is composed of an electrically insulating substrate material which is laminated on both sides with a copper foil and, on its side facing away from the component, is connected via an electrically insulating adhesive layer to a metallic, plate-shaped cooling element. In order to improve the thermal conductivity, the substrate material is provided with holes, which are filled with an electrically conductive material and in this way permit better heat conduction between the two copper films.
In the case of the known mounting configuration, a relatively large number of holes per component are needed through the substrate material in order to achieve adequate heat conduction through the substrate material. This requires a relatively high outlay on production and is therefore costly. In addition, a relatively thick electrically insulating substrate is necessary, which is merely used for mechanical stabilization but provides no contribution to the thermal dissipation.
It is accordingly an object of the invention to provide a mounting configuration of electric and/or electronic components on a printed circuit board which overcomes the above-mentioned disadvantages of the prior art devices of this general type, which ensures good thermal dissipation and at the same time can be produced simply and therefore inexpensively.
With the foregoing and other objects in view there is provided, in accordance with the invention, a mounting configuration. The mounting configuration contains components each having connecting pins and a printed circuit board having an insulating layer and at least two metallic plates insulated electrically from one another by the insulating layer. The two metallic plates and the insulating layer have holes for receiving the connecting pins of the components mounted on the printed circuit board, and through the holes the connecting pins are plugged and connected electrically to one of the two metallic plates. Preferably the components are electrical and/or electronic components such as electrolytic capacitors.
The mounting configuration according to the invention has a printed circuit board that is formed by at least two metallic plates that are connected to one another by an electrically insulating, insulating layer that conducts heat well. In this case, the thickness of the metallic plates can be selected suitably in a simple way in order to ensure the necessary heat transport. One of the two metallic plates will normally be connected to a ground potential and the other to the supply voltage potential.
The special advantage of the configuration resides in the very low-resistance and low-inductive connection of the electric and/or electronic components. Both the thermal dissipation and the inductance are more beneficial the thinner the insulating layer. In addition, the capacitance of the two metallic plates assumes a value in the range of about 1 pF in the case of a very thin insulating layer, as a result of which a filtering effect with respect to electromagnetic interference occurs.
The two plates have substantially concentric holes, through which the connecting pins of electric and/or electronic components, in particular of electrolytic capacitors, are plugged. Holes located one above another advantageously have different diameters in such a way that the hole in the metallic plate which is not electrically connected to the respective connecting pin has a larger diameter. In this way, a contact between a connecting pin and the metallic plate to which it is not to be connected can be avoided better and, the risks that the material with which the contact pins are connected to the respective metallic plates, for example tin solder, will come into contact with the other plate is reduced substantially.
In a development of the invention, the connecting pins have different lengths, so that the connecting pins that are connected to the metallic plate facing the component and belonging to the printed circuit board do not project into the hole in the other metallic plate.
In order to rule out to a great extent contact between the connecting pin which is connected to the metallic plate on the side of the printed circuit board facing away from the component, in a particularly advantageous development of the invention, the connecting pin is provided with an insulating sleeve, which can be connected to the component housing. The insulating sleeve additionally advantageously ensures protection against pole transposition of the component, which is of special importance in particular in the case of electrolytic capacitors, since the connecting pin with the sleeve does not fit through the other hole with a lower diameter.
In a development of the mounting configuration according to the invention, a further metallic plate can be disposed on the side of the printed circuit board facing away from the component, for the purpose of further cooling, and is likewise isolated from the other metallic plate by an electrically insulating layer.
The electrically insulating layers can be any desired adhesives, in particular adhesives that conduct heat well. However, use can also be made of double-sided adhesive films, since these are particularly easy to handle.
An important feature of the mounting configuration according to the invention is that it dispenses with an insulating substrate material, such as is regularly used in conventional printed circuit boards, and the stability of the printed circuit board is effected by the relatively thick metallic plates, while the insulating intermediate layers merely fulfill the function of the mechanical connection.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a mounting configuration of electric and/or electronic components on a printed circuit board, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.